HONG KONG: Much has been written about the rise of Chinese nationalism and its implications for the stability of Northeast Asia. But Korean nationalism could prove to be just as destabilizing.

The two Koreas, even combined, are no match for China's economic and military might. But the latent intensity of nationalism on both sides of the peninsula's demilitarized zone is more focused and potent.

For all their political and economic differences, the two Koreas sometimes seem to share a paranoia about foreigners. The recent mass demonstrations against U.S. beef imports are a case in point. This may be a passing issue, having much to do with domestic politics and inept management on the part of President Lee Myung Bak. But the mix of nationalism, anti-Americanism and sheer unwillingness to accept both the opinion of the World Health Organization and the global trading rules to which South Korea owes much of its prosperity was shocking.

The almost hysterical opposition to American beef imports may not sway the government in Seoul, which can still focus on larger issues, particularly the U.S.-Korea free trade pact. But it has left a nasty taste and been a reminder of the other aspects of Korean nationalism in South Korea that continue to irritate foreign trading partners.

The Korea which wants to buy up manufacturers in the United States - currently it has its eyes on GE's household appliance industry - as well as banks in Indonesia and golf courses in the Philippines continues to put huge bureaucratic obstacles in the way of foreign acquisitions of, for example, Korea Exchange Bank.

The beef demonstrations were the occasion not only for drumming up anti-Americanism in the name of public health but for some extreme expressions of nationalism.

For allowing in U.S. beef, President Lee was variously been compared to the minister who helped Japan annex Korea in 1910 and the emperors who paid tribute to China. The candle-carrying mass of demonstrators sang a song about the glorious days when Korea was not only united but extended over a much wider territory encompassing part of Manchuria, now Chinese, and a slice of the Russian Far East.

For all their historical links with China, Koreans sometimes like to see themselves as kin, however distant, of the non-Han peoples of mainland Northeast Asia now under Chinese and Russian rule.

The surge in national sentiment owes much to the fact that few southerners now see North Korea as a real threat. Pity has replaced fear. But China itself also must take some blame. Its recent attempt to claim ethnic Korean landmarks - notably the semi-sacred Mount Paekdu - and ancient Manchurian kingdoms as part of China's cultural history has naturally helped spur Korean sensitivities and remind Koreans that what was once their heartland is now a part of China. Koreans were in Manchuria centuries before the region became part of China with the Manchu conquest in the 17th century.

None of this is going to seriously undermine relations with China any time soon. The China market is too big, the need for Beijing's cooperation in dealing with Pyongyang too great. Likewise, the beef issue is not going to cause a major rift with the United States, which is still needed as a trade partner and regional guard - though it could help kill the free trade deal now opposed by Barack Obama.

But Asian countries are going to need more cooperation, not less, in the years ahead, as improved regional arrangements will be needed to compensate for the gradual erosion of the American-led system put in place after World War II. The last thing anyone needs is revanchist thoughts about "lost territories," real or imagined, or cries of "traitor" directed at presidents who make constructive deals with trading partners.

The beef demonstrations have been a reminder of official attitudes in the North, where history is seen as a series of battles against foreigners, with the United States and Japan as the chief villains, and where support from China and (previously) Russia was admitted grudgingly amid suspicion that the two countries were acting in their own self-interest.

The similarity of gut nationalism in North and South Korea makes their neighbors wary of unification, even if it could come about in the most peaceful and gradual way.

Of course, the Koreans have their legitimate grievances against foreigners - the Japanese, Chinese, Americans and Russians who have used them as pawns in wider wars. But these rivalries have mostly abated. Meanwhile, South Korea has become a successful, technologically advanced middling power in its own right. It has the capacity to play an important balancing role in East Asia's future. But it also has the capacity to focus on its old grievances, to nourish revanchist thoughts and to sow discord with neighbors in pursuit of the aspirations of its nationalists. And thus, the beef protests were a very poor reflection on the country of Samsung Electronics and the UN secretary general, Ban Ki Moon.